The present invention relates to photovoltaic devices and more particularly to an amorphous silicon-amorphous silicon carbide photovoltaic device.
Alternative methods of generating electrical power have recently received much publicity. Photovoltaic devices, and in particular solar cells, have been considered as a means for fulfilling at least a portion of the nation's growing energy needs. Solar cells are devices which are capable of converting solar radiation into usable electrical energy. Photovoltaic devices prepared by a glow discharge in silane have recently met with success in generating inexpensive electrical energy from sunlight. Such devices are taught in U.S. application Ser. No. 710,183, entitled "A Semiconductor Device Having A Body of Amorphous Silicon and Method of Making the Same" by David E. Carlson. Some of these devices have been found to have surface states which function as efficient recombination centers at layer interfaces. As a result of these recombination centers, carriers generated near these interfaces of the solar cell often disappear before reaching the high field region of the solar cell, and thus cannot be collected as current. Furthermore, in Schottky barrier amorphous silicon cells, in order to reduce the internal resistance of the solar cell, the metallic conducting layer at the incident surface should be thick. However, increasing the thickness of this surface layer reduces the amount of light penetrating the device, consequently decreasing its photovoltaic efficiency. Therefore, it would be most desirable in the field of amorphous silicon photovoltaic devices if the aforementioned problems could be overcome.